In vertebrate animals, the heart is a hollow muscular organ having four pumping chambers: the left and right atria and the left and right ventricles, each provided with its own one-way valve. The natural heart valves are identified as the aortic, mitral (or bicuspid), tricuspid, and pulmonary, and are each mounted in an annulus comprising dense fibrous rings attached either directly or indirectly to the atrial and ventricular muscle fibers.
Heart valve disease is a widespread condition in which one or more of the valves of the heart fails to function properly. Diseased heart valves may be categorized as either stenotic, wherein the valve does not open sufficiently to allow adequate forward flow of blood through the valve, and/or incompetent, wherein the valve does not close completely, causing excessive backward flow of blood through the valve when the valve is closed. Valve disease can be severely debilitating and even fatal if left untreated.
Valve disease involving the mitral valve often involves secondary mitral regurgitation (MR), a complication of end-stage cardiomyopathy which is the backflow of blood from the left ventricle (LV) to the left atrium (LA) resulting from imperfections in the mitral valve. When the mitral valve allows blood to flow backward into the left atrium, the left ventricle must pump progressively harder to circulate blood throughout the body, which in turn promotes congestive heart failure (CHF).
Various surgical techniques may be used to repair a diseased or damaged valve. One method for treating defective valves is through repair or reconstruction. One repair technique that has been shown to be effective in treating incompetence is annuloplasty, in which the effective size and/or shape of the valve annulus is modified by securing a repair segment, such as an annuloplasty ring, around the heart valve annulus. For example, the valve annulus may be contracted by attaching a prosthetic annuloplasty repair segment or ring to an interior wall of the heart around the valve annulus. The annuloplasty ring is designed to support the functional changes that occur during the cardiac cycle: maintaining coaptation and valve integrity to prevent reverse flow while permitting good hemodynamics during forward flow.
The annuloplasty ring typically comprises an inner substrate, often formed from a metal (such as stainless steel or titanium) or from a flexible material (such as silicone rubber or Dacron cordage), which is typically covered with a biocompatible fabric or cloth to allow the ring to be sutured to the heart tissue. Depending on a particular application, annuloplasty rings may be stiff or flexible, may be split or continuous, and may have a variety of shapes, including circular, D-shaped, C-shaped, saddle-shaped, and/or kidney-shaped. Examples are seen in U.S. Pat. Nos. 5,041,130, 5,104,407, 5,201,880, 5,258,021, 5,607,471, 6,187,040, and 6,805,710, the contents of which are incorporated herein by reference in their entirety. Many annuloplasty rings are formed in a plane, but some rings are generally non-planar. Such non-planar rings can be saddle-shaped, and/or bowed along various portions, such as being bowed along their anterior or straight side to conform to the desired shape of the annulus at that location.
Implanting of annuloplasty rings can be a difficult procedure. Currently-available methods include open-heart surgery and so-called minimally-invasive procedures. One particular difficulty is firmly holding the ring during the surgery. It is possible to implant rings by clamping the ring with forceps and/or the surgeon's fingers, but in many circumstances a specifically tailored annuloplasty ring holder is desirable. Examples of annuloplasty ring holders are depicted in U.S. Pat. Nos. 5,350,420; 5,683,402; and 6,749,630, the contents of which are incorporated herein by reference in their entirety.
Using a standard atriotomy approach to the mitral valve for repair, the surgeon does not generally achieve straight-on access to the mitral valve annulus. Instead, the surgeon often sees and accesses the valve from an angle. Therefore, when the sutures are placed in the annuloplasty ring and it is “parachuted” down to the annulus, the ring and holder must be reoriented to sit flat against the annulus. In minimally-invasive (MIS) approaches to the mitral valve, the annuloplasty ring must be passed through a relatively small port into the chest. This can be complicated by the bulk of some holders, so in some instances a surgeon simply removes the holder from the ring prior to “parachuting” the ring down the sutures and onto the valve annulus. However, the removal of the entire holder from the ring can make control of the annuloplasty ring more difficult.
Another issue is visibility of the ring and valve annulus during the implantation procedure. Some holders block significant portions of the surgeon's view, which can make the surgical procedure more difficult. To enhance visibility, some holders make use of transparent and/or translucent materials. Some holders use a so-called “window” approach, wherein openings are positioned in the template portion of the holder. The openings serve as windows in the holder template through which the user can view the surgical procedure. Examples of such holders are described in U.S. Pat. Nos. 5,683,402 and 6,749,630, the contents of which are incorporated by reference herein in their entirety.
Another issue is securing the ring to the holder in a releasable but secure manner. Many holders use multiple retaining sutures to secure a ring to the holder. In order to release the ring from the holder, the user severs the retaining sutures. Increasing the number of sutures can cause the ring to be more securely held to the holder, but can increase the steps necessary for the surgeon to release the ring from the holder. Additionally, the positioning of the retaining sutures is important in that the user must be able to access and sever the sutures to release the ring from the holder. Many prior ring holders made use of suture wells located at various positions about the holder, with the location of such wells corresponding to locations about the ring including the posterior and anterior portions of the ring. During implantation procedures, some of these locations may be difficult for a surgeon to access in order to sever the suture.
Accordingly, there has been a need for an improved apparatus, system, and method to implant an annuloplasty ring. The present invention satisfies one or more of these needs.